作者:Lei Zhang、Myoung-Mo Lee、Soo-Mi Lee、Jihye Lee、Maosheng Cheng、Byeong-Seon Jeong、Hyeung-geun Park、Sang-sup Jew
DOI:10.1002/adsc.200900787
日期:2009.12
e with C(9S)-aminodihydroquinine or C(9R)-aminodihydroquinidine and successively applied to the Michael addition of dimethyl malonate to nitroolefins as very efficient chiral Lewis acid bifunctionalorganocatalysts (up to >99% ee).
progress has been made toward the development of metal-free catalysts of enantioselective transformations, yet the discovery of organic catalysts effective at low catalyst loadings remains a major challenge. Here we report a novel synergistic catalyst combination system consisting of a peptide-inspired chiral helical (thio)urea oligomer and a simple tertiary amine that is able to promote the Michael reaction
Salt of the earth: The first chiral, coordinative alkaline earth metal catalysts have been developed. These catalysts effectively promote catalytic asymmetric additions of β‐dicarbonyl compounds to nitroalkenes in high yields with high enantioselectivities (up to 96 %).
chemical modification of a chiraldiamineligand may produce a robust and recyclable enantioselective catalyst. Metallopolymers based on chiral cyclohexyldiamine‐containing ditopic ligands and nickel(II) complexes have been readily prepared and applied in catalytic enantioselectiveMichaeladditions of 1,3‐dicarbonyl compounds to nitroalkenes. High yields and good enantioselectivities have been obtained and
Unprecedented Hydrophobic Amplification in Noncovalent Organocatalysis “on Water”: Hydrophobic Chiral Squaramide Catalyzed Michael Addition of Malonates to Nitroalkenes
作者:Han Yong Bae、Choong Eui Song
DOI:10.1021/acscatal.5b00685
日期:2015.6.5
In this study, water was demonstrated to be an exceptionally efficient reaction medium for the noncovalent, hydrogen-bonding-promoted enantioselective Michaeladdition of malonates to diverse nitroolefins using cinchona-based squaramide catalysts. A significant increase in the reaction rate was observed when the reaction was performed “on water” rather than in the conventional organic solvents, because